Counterbalanced door for an oven door



July 9, 1963 F. L. MILBURN 3,096,755

COUNTERBALANCED DOOR FOR AN OVEN DOOR Filed Aug. 30, 1961 4 Sheets-Sheet 1 T :5 2,: IN V EN TOR. a 1 Frank L. M/lbum His Af/ome y July 9, 1963 F. L. MILBURN COUNTERBALANCED DOOR FOR AN OVEN DOOR 4 Sheets-Sheet 2 Filed Aug. 50, 1961 HIS Attorney 2 w Em July 9, 1963 F. L. MILBURN 3,095,755

' COUNTERBALANCED DOOR FOR AN OVEN DOOR Filed Aug. 30, 1961 4 Sheets-Sheet 3 SIlllllll'lll'lllll'lll'lhl'l ||I||| O Fig. 6 Fig. 3

\ INVENTOR. Frank L. Mi/bum July 9, 1963 F. L. MILBURN COUNTERBALANCED DOOR FOR AN OVEN DOOR 4 Sheets-Sheet 4 Filed Aug. 50, 1961 INVENTOR. Frank L. Mi/bum Fig.4

United States Patent 3 096 755 COUNTERBALANCEDbObR FOR AN OVEN DOOR Frank L. Milburn, Bellbrook', Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Aug. 30, 1961, Ser. No. 134,929 9 Claims. (Cl. 126-191) This invention relates to a domestic appliance and more particularly to an improved counterbalancing arrangement for a vertically liftable oven door.

Accordingly it is an object of this invention to provide an oven with a vertically liftable door having a compact counterbalancing system.

A more specific object of this invention is the provision of an oven door moving vertically between a closed position, an open position and an intermediate partially open position and wherein said door is supported for movement between said positions by a spring biased crank arm which cooperates with a detent for positioning said door in certain of said positions.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein preferred embodiments of the present invention are clearly shown.

In the drawings:

FIGURE 1 is a fragmentary perspective view of a built-in range set forth more particularly in copending application Serial No. 19,081 filed March 31, 1960, and assigned to the same assignee as this invention;

FIGURE 2 is a sectional view of the counterbalancing arrangement of this invention taken along line 22 in FIGURE 3 and with parts broken away;

FIGURE 3 is a fragmentary side view with parts broken away to show the door counterbalancing arrangement with the door closed;

FIGURE 4 is a fragmentary side view with parts broken away to show the counterbalancing arrangement with the door in a partly open or a fully open position;

FIGURE 5 is an enlarged fragmentary sectional view taken along line 55 in FIGURE 2 to show the detent portion of the counterbalancing arrangement; and

FIGURE 6 is an enlarged fragmentary sectional view taken along line 66 in FIGURE 2 to show the counterbalance adjusting means.

In accordance with this invention and with reference to FIGURE 1, an integral counter top range 10 is shown. The range 10 is adapted to be built in to a line of base cabinets which abut the sides of the rangethe range setting on a matching base cabinet 12 which may be used for storing cooking utensiles and the like. Generally, the range 10 includes a casing 14 having outer side walls or panels 16 and 18. The outer side panels 16 and '18 define generally a control section 20, an oven compartment 22 and a cooking top drawer 27. The front of the oven compartment is closed by an oven door 24 having a handle 26 for lifting'the door to its fully open position (shown in FIGURE 4) to expose the interior of the oven compartment 22. The cooking top drawer 27 is adapted to be slidably positioned within the side walls 16 and 18 or exposed as shown in FIGURE 1. Further details as to range construction may be obtained from the aforementioned copending application.

In general, the oven door 24 is positioned as shown in FIGURE 3 for closing the oven compartment 22 and as shown in FIGURE 4 in solid line for opening the oven door to expose the oven compartment or as shown in phantom line for opening the door to an intermediate position for venting the oven during broiling.

A counterbalancing arrangement and support for the oven door 24will now be more fully explained. With Patented July 9, 1963 reference to FIGURE 3, the door 24 is shown supported on its right side (as viewed in FIGURE 1) by an upper control arm 30 and a lower control arm 32. Similarly and with reference to FIGURE 2, on the left side of the door an upper control arm is pivotally supported at its outer end to the door 24 while a lower control arm 37 is likewise pivotally connected to the oven door. Again with reference to FIGURES 2 and 3, the casing 14 is shown with a portion of its side wall 18 broken away to expose an insulation retainer 34 adjacent which the lower control arm 32 is pivotally attached to a pin 36 carried on a depending control arm adjusting bracket or L-shaped metal strip 38. This adjusting bracket extends from the control compartment 20 through a slot 39 in the bottom wall or partition 40 at the corner of the control compartment into the space between the insulation retainer 34 and the casing side wall 18. Within the control compartment the adjusting strip 38 is bent over to form a flange 42 having an elongated slot 44 for receiving a set screw 46 which screws to the partition 40. The lower control arm adjustment is made possible by loosening the set screw 46 and shifting the adjusting bracket 38 from front to back to locate the pivot point 36 for the lower control arm in a manner to position the inner door panel 150 of the door 24 in coplanar relationship to the front of the oven. It is important to effect proper sealing of the oven liner 52 forming the oven compartment 22.

The insulation retainer 34 extends horizontally inwardly beneath the control compartment to define a top insulation retainer wall portion spaced from the oven forming liner 52, thereby to retain therebetween any conventional heat insulation such as 54. The partition 40 forms the bottom wall of a generally open-top foldedup, box-like structure which defines in part the controls compartment 20-a cover 55 being removable for servicing the counterbalancing mechanism as well as the controls. A front wall portion 53 at the front of the partition 40 supports a range control switch such as 56.

Afiixed to the partition 40 and upstanding therefrom is a right-hand control arm counterbalance arrangement shown generally at 57 and a similar left-hand control arm counterbalance arrangement at 160 (FIGURE 2). In general, the counterbalance serves to pivotally and spring biasingly support the inner ends of the upper control arms on a transverse shaft 62. The following description of the right upper control arm 30 and its relationship to the counterbalance 57 is regarded as sulficient to disclose clearly the relationship of the left upper control arm 35 and the counterbalance 160.

The counterbalancing and :door positioning arrangement of this invention is best seen in FIGURES 2 and 5. With .particular reference to the right-hand control arm mechanism the counterbalancing assembly 57 is shown comprised of a U-shaped spring retainer bracket 53 fastened by set screws to the control compartment bottom wall or partition 40. Note that the bottom wall 72 of the U-shaped spring retainer bracket is slotted as at 74 to provide a measure of adjustment for the spring retainer from back to front relative to the oven door. The rear or back end of the spring retainer bracket 59 is provided with an interfitting adjusting screw retaining bracket 76 which is generally V-shaped and provided with a top and bottom strengthening flanges 80. The screw retaining bracket 76 is dove-tailed in a notch at the back of the bracket 58 and serves to position the adjusting head 82 of an ad justing bolt 84 which extends longitudinally of the spring retainer bracket 58. A door tensioning spring 88 envelops the adjusting bolt 84 and is provided with a few convolutions of reduced diameter as at 90 (FIGURE 6) which snugly retain a tapered nut 92 threadedly engaged with the adjusting bolt 84. At the opposite end of the spring 88 a door positioning pawl 98 is provided with an attachment flange 100 which is fastened as by welding at 102 (see FIGURE 5) to the transverse shaft 62. Thus whenever the oven door 24 is raised or lowered, the pivoting action of the shaft 62 will serve to move the end 138' of the pawl 98 in an arcuate path. Since the spring 88 is provided with a hook portion 104 engaged with the pawl in a nylon bushing Hi5, the spring 88 is alternately stretched and relaxed as the door is moved. In particular, when the door is in its raised position as seen in FIGURE 4, the springs 88 serve as the biasing means for retaining the'door 24- in its raised position. Although FIGURE 2 shows two springs SSfor biasing the door into its raised position, it should be understood that one spring will suffice if properly designed to counterbalance the full weight of the oven door.

The transverse-shaft 62 is journalled at each side of the control compartment and the detail of this journalling is best seen in FIGURE 5. Note that the spring retainer bracket 58 is provided with an inner side wall 106 and an outer side wall 1%. Both side walls 1&6 and 108 are notched along a radius 110 to receive a nylon journalling block 112. This journalling block 112 has a rectangular flange portion 114 which abuts the inside of the outer wall 108 of the bracket and is fastened thereto as by screws 1 15. Outboard of the spring retainer bracket 58 and its outer wall 1118 the nylon block 112 is provided with an in- 'tegral journalling portion 116 which extends from the bracketwall 108 to a bearing washer12tl fastened to the Inner side of' the upper control arm portion 60'. Thus the upper control arm 30' is adequately positioned for movement within a cutout 122 in the control compartment :104 interffitted with the door positioning pawl 98 and its back portion 90 secured through the bolt 84 with the bracket 76 to retain the entire counterb alancing assembly in assembled relationship. In other words, the spring 38 holds the pawl 98 and the pawl holds the transverse shaft 62 nested within the notch 123 of the nylon journal block.

This, in turn, causes the journal block 112 to be held firmly within the notch 110 of the spring retainer bracket 58 as seen clearly in FIGURE 5.

Turning again to FIGURE 5 the detent arrangement for positioning the door in either the closed or the broil position will now be more clearly set forth. A leaf spring detent 126 is provided with an angular attachment flange 128 positioned on the bottom wall of the spring retainer bracket 58-fastening means such as screws 130 interfitting with the control compartment bottom wall 40 to positively locate the detent 126. Note that slots 132 in the bottom wall of the spring retainer bracket provide for a measure of detent adjustment. The upper end of the detent 126 is provided with a reverse bent keeper portion which forms a door closed stop position 134 and a broil stop position 136. The pawl 98 has a nylon tip 138 which nests in the door closed stop 134 as shown 'in FIGURES and FIGURE 3 --the angular relationship of the spring stop position 134 serving to cam the pawl button 138 downwardly to provide a constant sealing bias to the door 24 in the closing direction. When the pawl-98 is in a position to place the nylon button 138 on the broil stop 136 as seen in FIGURE 4, the door 24 is positioned in a partially open relationship to the oven compartment 22. The gap so formed provides for venting the oven compartment during broiling.

When the oven door 24 is moved to its raised position as seen in solid line in FIGURE 4, the pawl 98 moves away from the 1detent126 and the spring 88 serves as the sole means for retaining the door in its upper position.

Thus to insure that an arrangement is provided whereby differently weighted doors24 may beretained, an adjusting mechanism shown generally at 140 (FIGURE 6) is provided. This assembly includes a portion of those elements described hereinbefore in connection with the counterbalancing arrangement and includes the reduced end 90, the spring 88 and the'adjus'ting'nut 92 which threadedly engages the adjusting bolt 84. Since the head 82 of the adjusting bolt 84 extends behind the screw retaining bracket 76, a washer 142 isinterposed between the head and the bracket 76. Thus whenever the bolt head 82 is rotated, the stress on spring 88 may be varied. The heavier the door 24, the greater the tension necessary on spri-ng88 to counterbalance the weight of the door and to retain the door in its raised position. Of course, the tension on the spring 88 must not overbalance the restnaining'etfect of the detent 126 when the pawl is in either its broil stop or its door closed position.

Referring now to 'FIGUREZ, the upper control arm 31) is shown pivotally connected to the inner door panel and nested between the side flange of the inner door panel and a rearwardly turned flange 152 on the outer door panel 154. Further details relative to this constiuction may be gained from the aforementioned copendmg application.

The description of the counterbalancing arrangement of this invention has been given with reference to the righthand system 57 for the control arms 30 and 32. It should be understood that the left-hand control arms 35 and 37 are similarly jour'nalled on a counterbalancing arrangement which is substantially like the arrangement 57, but without the detent spring 126like parts carrying like reference numerals.

It should now be seen that an improved counterbalancing arrangement has been provided for a vertically liftable oven door. The assembly is provided with an openslotted or notched nylon hearing which in cooperation with a counterbalance spring retains the transverse shaft in the journalling slot. In this way, complete journalling of transverse shaft is unnecessary. Further, a simplified method of detenting the door pawl is taught whereby the oven door may be adjustably retained in its raised open position, its intermediate broil position or its lowered closed position. All of the foregoing advantages are built into a compact counterbalancing and door detent arrangernent which leaves ample room for electrical components within the control compartment of the range.

While the embodiments of the present invention as herein disclosed constitute preferred forms, it is to be understood that other forms might be adopted.

What is claimed is as follows: 1. In combination, a casing defining an oven compartmenthaving a from opening, a door having a first ver- 55 tically disposed-position for closing said opening, a secfposition for'exposing said opening and a third position between said first and second positions for venting said ond generally vertically disposed position above said first compartment, and means for counterbalancing said door relative to said casing as said door moves between said positions, said'counterbalancing means comprising control arm means for supporting said door, a transverse shaft for pivotally supporting said control arm and having a pawl portion, a spring retainer aflixed to said casing and having an open ended slot at one end thereof facing forwardly for journalling said shaft, a spring in said spring retainer connected at one end to said pawl portion and at its other end to said spring retainer to retain said shaft in said slot, adjusting means on said spring retainer threadedly engaged with said spring for adjusting the tension on saidspring, and a spring'detent afiixed to said casing and having a yieldable keeper portion in coplanar relationship to said pawl portion, said keeper portion having a first stop for camming said pawl portion to move said door toward said first vertically disposed closed position, a'second stop for cooperating with said pawl portion to hold said door in said third venting position, said spring cooperating with said pawl portion to retain said door in said second vertically disposed open position.

2. In combination, a casing defining an oven compartment having a front opening, a door having a first vertically disposed position for closing said opening, a second generally vertically disposed position above said first position for exposing said opening and a third position between said first and second positions for venting said compartment, and means for counterbalancing said door relative to said casing as said door moves between said positions, said counterbalancing means comprising control arm means for supporting said door, a transverse shaft for pivotally supporting said control arm and having a pawl portion, a spring retainer afiixed to said casing and having an open ended slot at one end thereof facing forwardly for journalling said shaft, a spring in said spring retainer connected at one end to said pawl portion and at its other end to said spring retainer to retain said shaft in said slot, and a spring detent afiixed to said casing and having a yieldable keeper portion in coplanar relationship to said pawl portion, said keeper portion having a first stop for camming said pawl portion to move said door toward said first vertically disposed closed position, a second stop for cooperating with said pawl portion to hold said door in said third venting position, said spring cooperating with said pawl portion to retain said door in said second vertically disposed open position.

3. In combination, a casing defining an oven compartment having a front opening, a door having a first vertically disposed position for closing said opening and a second generally vertically disposed position above said first position for exposing said opening, and means for counterbalancing said door relative to said casing as said door moves between said positions, said counterbalancing means comprising control arm means for supporting said door, a transverse shaft for pivotally supporting said control arm and having a pawl portion extending at an angle therefrom, a spring retainer affixed to said casing and having an open ended slot at one end thereof facing forwardly for journalling said shaft, a spring in said spring retainer connected at one end to said pawl portion and at its other end to said spring retainer to retain said shaft in said slot, and a spring detent afiixed to said casing and having a yieldable keeper portion in coplanar relationship to said pawl portion, said keeper portion having a first stop for camming said pawl portion to move said door toward said first vertically disposed closed position, and said spring cooperating with said pawl portion to retain said door in said second vertically disposed open position.

4. In combination, a casing defining an oven compartment having a front opening, a door having a first vertically disposed position for closing said opening, a second generally vertically disposed position above said first position for exposing said opening and a third position between said first and second positions for venting said compartment, and means for counterbalancing said door relative to said casing as said door moves between said positions, said counterbalancing means comprising control arm means having an outer end for pivotally supporting said door along a side thereof, a transverse shaft over said oven compartment and generally parallel to said door for pivotally supporting an inner end of said control arm and having a pawl portion extending from said shaft, a spring retainer affixed to said casing and having an open ended slot at one end thereof facing forwardly for journalling said shaft, a spring in said spring retainer connected at one end to said pawl portion and at its other end to said spring retainer to retain said shaft in said slot, adjusting means on said spring retainer threadedly engaged with said spring for adjusting the tension on said spring, and a spring detent aflixed to said casing and having a yieldable keeper portion in coplanar relationship tosaid pawl portion, said keeper portion having a first stop for 6 camming said pawl portion to move said door toward said first vertically disposed closed position, a second stop for cooperating with said pawl portion to hold said door in said third venting position, said spring cooperating with said pawl portion to retain said door in said second vertically disposed open position.

5. A counterbalance arrangement for a door moving vertically relative to a compartment and comprising, control arm means for supporting said door and having a pawl portion, means adapted to be positioned in said compartment for pivotally mounting said control arm and said pawl portion, detent means adapted to be fixed relative to said compartment and in coplanar relationship to said pawl portion, said detent means having a first stop engageable with said pawl portion for positioning said door in a first position and a second stop engageable with said pawl portion for positioning said door in a second position, and a spring means adapted to have one end fixed relative to said compartment and another end fastened to said pawl portion to withdraw said pawl portion away from said detent means for retaining said door in a third position.

6-. The counterbalance arrangement of claim 5 including an adjusting means adapted to be spacially fixed relative to said compartment and wherein said one end of said spring is threadedly engaged with said adjusting means.

7. A counterbalance arrangement for a door moving vertically relative to a compartment between a closed position and an open position and comprising, control arm means for supporting said door and having a pawl .portion movable with said control arm means, means adapted to be located in said compartment for pivotally mounting said control arm and said pawl portion, detent means adapted to be fixed relative to said compartment and in coplanar relationship to said pawl portion, said detent means having a stop continuously biasingly engaging said pawl portion when said door is in said closed position for biasing said door into said closed position, and a spring means adapted to have one end fixed rela tive to said compartment and another end fastened to said pawl portion for biasing said door into said open position.

8. In combination, a casing defining an oven compartment having a front opening, a door having a first vertically disposed position for closing said opening and a second generally vertically disposed position displaced from said first position for exposing said opening, and means for counterbalancing said door relative to said casing as said door moves between said positions, said counterbalancing means comprising control arm means for supporting said door along a side thereof, a transverse shaft generally parallel to said door for pivotally supporting said control arm and having a pawl portion extending from said shaft, a spring retainer affixed to said casing at generally right angles to said shaft and having an open ended slot at one end thereof facing forwardly for journalling said shaft, and a spring for said spring retainer connected at one end to said pawl portion and at its other end to said spring retainer as the sole means for retaining said shaft in said slot, said spring cooperating with said pawl portion to retain said door in said second vertical-1y disposed position.

9. A counterbalance arrangement for a door moving vertically relative to a compartment and comprising, control arm means for supporting said door and having a first member, means adapted to be located in said compartment for pivotally mounting said control arm and said first member, a second member adapted to be fixed relative to said compartment and in coplanar relationship to said first member, one of said members having a first stop engageable with the other of said members for positioning said door in a first position and a second stop 7 S- engageable with said other of said members for position- References Cited in the file of this patent ing said door in a secondjposition, and a y-i-eldahlemeans 7 adapted to have one end fixed relative 'to said eompa'rt- UNITED STATES PATENTS ment and another end fastened to said other :of said 2, 8 ,968 "Eokhmd Oct. 4, 1949 members to withdraw said other of said members away 5 2j58fhl404 Whb :Feb. 5, 1952 from said one of said members 'for retaining said .d'oor 239123 7 Snyder Nov. 10, 1959 in -a third position. 2,979,353 Crispellwet a1. Apr. 11, 1961 

5. A COUNTERBALANCE ARRANGEMENT FOR A DOOR MOVING VERTICALLY RELATIVE TO A COMPARTMENT AND COMPRISING, CONTROL ARM MEANS FOR SUPPORTING SAID DOOR AND HAVING A PAWL PORTION, MEANS ADAPTED TO BE POSITIONED IN SAID COMPARTMENT FOR PIVOTALLY MOUNTING SAID CONTROL ARM AND SAID PAWL PORTION, DETENT MEANS ADAPTED TO BE FIXED RELATIVE TO SAID COMPARTMENT AND IN COPLANAR RELATIONSHIP TO SAID PAWL PORTION, SAID DETENT MEANS HAVING A FIRST STOP ENGAGEABLE WITH SAID PAWL PORTION FOR POSITIONING SAID 